ALSA: usb-audio: fix OOB write in snd_usbmidi_us122l_output()

Summary

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: fix OOB write in snd_usbmidi_us122l_output() The snd_usbmidi_us122l_output() picks a count of 2 on anything slower than high speed and never relates it to ep->max_transfer. The URB buffer holds exactly max_transfer bytes, so a device declaring a one byte bulk endpoint takes two bytes from snd_rawmidi_transmit(), and the memset that pads the rest computes 1 - 2 in int and wraps to SIZE_MAX. Only 0x800e and 0x800f are pinned to nine bytes. The US-122MKII at 0x0644:0x8021 falls to the default and takes usb_maxpacket(), which the USB core only clamps downward. The akai and novation output ops in this file were given the same guard recently. Do the same here.

Timeline

1. Sep 16, 2026, 10:33 AM UTCCVE published
2. Oct 19, 2026, 8:56 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 030a07e441296c372f946cd4065b5d831d8dc40c · fixed in 5538daf2a5cc80ac3f3e913c0db045d92d995d40; From 030a07e441296c372f946cd4065b5d831d8dc40c · fixed in a441a8e52148c91c2f2a91f42e3b9bc961a13a4b; From 030a07e441296c372f946cd4065b5d831d8dc40c · fixed in 2dae0e3a59e31f78222279d544b98e747cd1fbff; From 030a07e441296c372f946cd4065b5d831d8dc40c · fixed in 1d4add2b832b56f81bb0eab065ec35c610343018; From 030a07e441296c372f946cd4065b5d831d8dc40c · fixed in de6d252f115be887a701c09a05cdb076f3a590c9; From 030a07e441296c372f946cd4065b5d831d8dc40c · fixed in 9392a2c346762ffee8edd1ba8bac50d2e24a2ed7; From 030a07e441296c372f946cd4065b5d831d8dc40c · fixed in 9d81885d97cba7796d1f8edc88f2499c8296f5b9; From 030a07e441296c372f946cd4065b5d831d8dc40c · fixed in e4637ce34607f1733a34a57294966d26b263e626

• Linux Linux

  2.6.28

• KernelLinux

  From 2.6.28 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.51; From 6.19.0 · fixed in 7.2.5

References 8